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On the placement of actuators and sensors for flexible structures with closely spaced modes

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Science china(Technological Sciences) 2010年第7期53卷 1973-1982页

作者： LIU XiaoXiang1,2 & HU Jun1,2 1 beijing institute of Control Engineering, beijing 100190, china 2 State Key Laboratory of Science and technology on Space Intelligent Control, beijing 100190, china 1. beijing institute of Control Engineering Beijing 100190 China2. State Key Laboratory of Science and Technology on Space Intelligent Control Beijing 100190 China

This paper analyzed the fundamental limitations of previous work and developed a new method to optimally locate actuators and sensors for structures with close modes. Optimization criteria were defined based on the distinguishing modal controllability and observability measures of close modes. An appropriate genetic algorism was adopted as the optimization algorism. Solving the high order Lyapunov functions was avoided by means of the closed-form expressions for controllability and observability Grammians. Since structure with widely separated natural frequencies is approximately balanced, computational efficiency was improved by grouping close modes together and dealing with the resulting subsystems independently. Finally, the effectiveness and optimality of the novel placement scheme were verified on a model structure with close modes.

关键词： close modes controllability/observability sensor/actuator optimization criterion optimization algorithm

research on resolution between multi-component LFM signals in the fractional Fourier domain

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Science china(Information Sciences) 2012年第6期55卷 1301-1312页

作者： LIU Feng 1,XU HuiFa 1,2,TAO ran 3 & WANG Yue 3 1 Department of Electronic and Information Engineering,Naval Aeronautical Engineering institute,Yantai 264001,china 2 The 94362 th Unit of people's Liberation Army,Qingdao 266111,china 3 school of Information Science and technology,beijing institute of technology,beijing 100081,china 1. Department of Electronic and Information Engineering Naval Aeronautical Engineering Institute Yantai 264001 China2. The 94362th Unit of People’s Liberation Army Qingdao 266111 China3. School of Information Science and Technology Beijing Institute of Technology Beijing 100081 China

When the initial frequencies and chirp rates of multi-component linear frequency modulation (LFM or chirp) signals are close,the signals may not be distinguished in the fractional Fourier domain (FrFD).Consequently,some signals cannot be *** this paper,first,the spectral distribution characteristics of a continuous LFM signal in the FrFD are analyzed,and then the spectral distribution characteristics of a LFM signal in the discrete FrFD are ***,the critical resolution distance between the peaks of two LFM signals in the FrFD is deduced,and the relationship between the dimensional normalization parameter and the distance between two LFM signals in the FrFD is also *** is discovered that selecting a proper dimensional normalization parameter can increase the ***,a method to select the parameter is proposed,which can improve the resolution ability of the fractional Fourier transform (FrFT).Its effectiveness is verified by simulation results.

关键词： fractional Fourier transform LFM signal signal resolution

Fluorescence dynamics of interactions between polyamide pypypyβDp and DNA

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Science china Chemistry 2006年第1期49卷 75-80页

作者： ZHANG Huijuan1,2, WANG Jin3, WU Yishi1, YUAN Gu3, AI Xicheng1, WANG Li4 & ZHANG Jianping1 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species, institute of Chemistry, Chinese Academy of Sciences, beijing 100080, china 2. school of Life Science and technology, beijing institute of technology, beijing 100081, china 3. College of Chemistry and Molecular Engineering, peking University, beijing 100080, china 4. Center for Condensed Matter physics, institute of physics, Chinese Academy of Sciences, beijing 100080, china Correspondence should be addressed to Ai Xicheng and Zhang Jianping 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 2. school of Life Science and technology Beijing Institute of Technology Beijing 100081 China 3. College of Chemistry and Molecular Engineering Peking University Beijing 100080 China 4. Center for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The photophysical properties of the polyamide pypypyβDp (ppp) were investigated by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. It was found that the excited-state properties of ppp are very sensitive to solvents. In TKMC buffer ppp exhibited weak fluorescence with a decay time constant of 16 ps, while with the decrease of the solvent polarity ppp showed the blue-shifted peak position, increased inten-sity and lengthened life-time for its fluorescence behavior. In the presence of calf thymus DNA, it was observed that the fluorescence intensity was enhanced and the fluorescence lifetime increased from 16 to 32 ps for ppp, which verified that ppp bound into the minor groove of DNA duplex.

关键词： polyamide (ppp), calf thymus DNA (ctDNA), time-resolved fluorescence spectroscopy, recognition dynamics.

Kinetic characteristics of continuous flow polymerase chain reaction chip: A numerical investigation

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Science china(Technological Sciences) 2010年第7期53卷 1967-1972页

作者： WANG ShiYing1 & WANG Wei2,3 1 school of physics, peking University, beijing 100871, china 2 institute of Microelectronics, peking University, beijing 100871, china 3 National Key Laboratory of Science and technology on Micro/Nano Fabrication, beijing 100871, china 1. school of physics Peking University Beijing 100871 China2. Institute of Microelectronics Peking University Beijing 100871 China3. National Key Laboratory of Science and Technology on Micro/Nano Fabrication Beijing 100871 China

Continuous flow pCr (polymerase chain reaction) chip holds impressive advantages compared to micro chamber pCr chip. In order to have better understanding of kinetic characteristics of continuous flow pCr chip, a comprehensive mathematical model is presented in this paper, including melting, annealing and extension phases of a typical pCr process which has the essence of a convection-diffusion-reaction system. Using this model, we can simulate the pCr process in series of reaction cycles. Numerical results show that the average sample velocity plays a significant role in affecting the amplification efficiency. Also, appropriate combination of the pCr mixture is important for high-quality DNA amplification. Giving a large initial DNA concentration range, the continuous flow pCr scheme holds excellent real-time detection ability theoretically. The present numerical model bridges the temperature distribution to the real DNA amplification, and thereby is able to successfully predict continuous flow pCr properties which are important for the chip design.

关键词： continuous flow pCr chip numerical simulation convection-diffusion-reaction system

Different Aggregation Behaviors of Tetra-(4-hydroxyphenyl) porphyrin (THppH_2) in the Inner Core and on the Surface of CTAB Micelles

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Chinese Chemical Letters 2000年第10期11卷 929-930页

作者： Chen MA, Yun Hong ZHANG, Chang Song FU, Qian Shu LI (school of Chemical Engineering and Materials Science, beijing institute of technology, beijing 100081) beijing Inst Technol Sch Chem Engn & Mat Sci Beijing 100081 Peoples R China

The UV-Vis spectra of THppH2 in CTAB micelles at pH7.2 and pH11.0 were analyzed to study the effect of micellar environments on the aggregation behaviors of this porphyrin.

关键词： THppH_2 CTAB micelles aggregation UV-Vis spectra.

Noise helped manifestation of intrinsic frequency:A case study in the mesoscopic hormone signaling system

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progress in Natural Science:Materials International 2009年第10期19卷 1209-1214页

作者： Lin Ji a,,Yuanyuan Zhang a,Xiufeng Lang b,Wenxiang Hu a,Qianshu Li c a Department of Chemistry,Capital Normal University,beijing 100048,china b school of Science,beijing University of Aeronautics and Astronautics,beijing 100191,china c The institute for Chemical physics,beijing institute of technology,beijing 100081,china [a]Department of Chemistry Capital Normal University Beijing 100048 China [b]school of Science Beijing University of Aeronautics and Astronautics Beijing 100191 China [c]The institute for Chemical physics Beijing Institute of Technology Beijing 100081 China

The selective sustainment of nonlinear systems to signals is of great significance to signal transduction in living *** take hormone signaling as an example,and investigate the sustainment of internal and external *** results prove that signals with "intrinsic frequency",no matter if it is noise induced or external injected,can be selectively sustained by exploiting internal and/or external *** the internal and external noise can optimize the noise-induced signals,and the optimization is rather robust to the disturbance of external signals with other *** results are of significance for weak signal detection and transduction in the presence of external signals.

关键词： Noise Intrinsic frequency Mesoscopic system

Numerical and experimental investigation of the fracture behavior of shock loaded alumina

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 244-252页

作者： rEN HuiLan1,SHU XueFeng2 & LI ping3 1 State Key Laboratory of Explosion Science and technology,beijing institute of technology,beijing 100081,china 2 institute of Applied Mechanics and Biomedical Engineering,Taiyuan University of technology,Taiyuan 030024,china 3 Labroratory for Shock Wave and Detonation physics research,institute of Fluid physics,CAEp,Mianyang 610059,china 1. State Key Laboratory of Explosion Science and technology Beijing Institute of Technology Beijing 100081 China2. Institute of Applied Mechanics and Biomedical Engineering Taiyuan University of Technology Taiyuan 030024 China3. Labroratory for Shock Wave and Detonation Physics Research Institute of Fluid Physics CAEP Mianyang 610059 China

plate impact expeiments are conducted to investigate the dynamic behavior of alumina by using one stage light gas gun. A ve-locity interferometer system for reflectors (VISAr) is used to obtain Hugoniot elastic limit and the free surface velocity profile,which consists of an elastic wave followed immediately by a dispersive inelastic wave. The stress histories under different impact velocities are measured by in-material manganin gauges. Based on the experimental data a Hugoniot curve is fitted,which shows the compressive characteristics that alumina changes typically from elastic to "plastic" ,and under higher pressure it will be transferred to similar-fluid state. The turning point of the Hugoniot curve from a high pressure region to a low pressure region is about 11.4 Gpa. The fracture process of alumina is simulated by way of finite element code. After the analysis of the fracture mechanism,the numerical results show an important role played by the nucleation and the growth of the cracks in the macro-scopic fracture of the alumina target. The numerical predictions of stress histories are compared with the experimental results,which indicates consistency between them.

关键词： plate impact experiment hugoniot curve fracture characteristics numerical simulation

Numerical Modeling of NO Formation during packed-bed Combustion of Coke Granules

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 261-268页

作者： Chunbao Xu, Shengli Wu, Daqiang Cang (Metallurgy school, University of Science and technology beijing, beijing 100083, china institute for Chemical reaction Science, Tohoku University, Japan) Metallurgy school University of Science and Technology Beijing Beijing 100083 China institute for Chemical reaction Science Tohoku University Japan

A comprehensive kinetic model of NO formation during coke combustion in packed-bed in presence of noncombustible particles was developed. The detailed homogeneous gas-phase chemistry (including 102 chemical reactions), heterogeneous gas-solid chemistry (including 11 reactions) of coke combustion and NO formation, and the heat and mass transfer were taken into account in the present model. The governing equations which are strongly coupled, non-linear and unsteady with 26 unknowns in total, were dispersed into differential equations with the finite differential method. Meanwhile, all the differential equations were numerically solved to give the time-histories and space-distributions oftemperatures of the bed and gas phase as well as the concentrations of all the gaseous species. By comparison, the experimental data were explained well by the calculated results. Based on the kinetic and mathematical model, the effects of O2 content of inlet gas, the initial chemical analysis of coke, bed-temperature and local reductive atmosphere (CO/O2) on NO formation during packed-bed coke combustion were numerically discussed. It was found that coke samples with a higher initial content of [N] and volatile matters, combusted under a suitable O2-containing atmosphere produced less NO emission. The reactions between CO and NO, catalyzed by high temperature surface of coke particles may be responsible for efficient reduction of NO.

关键词： kinetic model NO formation combustion packed-bed coke Metallurgy

Measurement Methodology for Monitoring Fouling resistance in Condenser of Chiller

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湖南大学学报（自然科学版） 2009年第S1期36卷 119-122页

作者： YU Dan1,3,GAN Li-si1,CAO Yong2(1.beijing University of technology,beijing 100022,china 2.Build Environment and Energy Efficiency,china Academy of Building research,beijing 100013,china 3.beijing institute of Civil Engineering and Architecture,beijing 100044,china) beijing University of technology Beijing 100022 China beijing institute of Civil Engineering and Architecture Beijing 100044 China Build Environment and Energy Efficiency China Academy of Building Research Beijing 100013 China

This paper established an on-line monitoring model for fouling resistance of cooling water based on heat transfer theory,which was mainly applied to the fouling resistance test for condenser of chiller in operation,and the test requirements were *** proves that the load ratio of chiller has big influence on the test result,and the best load ratio for test is the range of 80%～100%.A case has been executed to validate the model's feasibility.

关键词： fouling resistance monitoring condenser cooling water